1. Field of the Invention
The invention relates to a coaxial reel system. More particularly, the invention relates to a reel assembly apparatus for coaxial magnetic tape reels.
2. Description Relative To The Prior Art
In the magnetic tape recording art, a coaxial supply/take-up reel assembly is particularly convenient if the recording apparatus is of the helical scanning type, because the tape enters a head scanning area at a level that is different from the level at which the tape leaves the scanning area. Even with other recording systems, such as longitudinal recording, it is desirable from the standpoint of saving space, to mount the tape supply reel and tape take-up reel coaxially with respect to each other.
The prior art coaxial reel systems involve rather complicated mechanisms for releasably attaching a pair of reels to their respective spindle drive assemblies. For example, U.S. Pat. No. 3,561,699 discloses coaxial reel apparatus in which each reel is fitted over a corresponding hub having an outer circumferential elastomeric ring. Screw means on the respective hubs cause axial compression of the corresponding elastomeric ring, with the axial compression causing the ring to bulge radially outwardly into engagement with the inner rim of the corresponding reel.
U.S. Pat. No. 3,322,365 discloses an alternate reel mounting arrangement in which rotatable clamping knobs for each of the spindle drive assemblies have a radially extending flange confronting a bevelled surface of the drive spindle, with a resilient elastic ring mounted between the flange and the bevelled surface. The rotating of a knob causes the corresponding flange to move axially to compress the ring, which thereby expands radially outwardly. The ring expands beyond the circumferential edge of the drive spindle to engage the corresponding tape reel, thereby locking the reel to the spindle.
In addition to their complexity, a further disadvantage of coaxial reel systems of the aforementioned type is that the elastomeric material is repeatedly stretched and tends to be weakened by the stretching. Furthermore, when both reels are mounted from the outboard side of the reel system, which is usually the case, the inboard reel may not be readily accessible because of the presence of the outboard reel and the outboard drive spindle. Accordingly, this often means that the outboard reel must be removed in order to make a mounting adjustment of the inboard drive spindle.
A further disadvantage of prior art coaxial reel assemblies, as exemplified by U.S. Pat. No. 3,322,365, is that when both reels are mounted from the outboard side, the mechanism for clamping the inboard reel to its drive spindle is often positioned axially between the adjacent reels. This arrangement prevents the reels from being positioned immediately adjacent each other, and thereby requires space which may not be available with tape recording apparatus of a compact design.